var twoSum = function(nums, target) {
    for (let i = 0; i < nums.length; i++) {
        for (let j = i + 1; j < nums.length; j++) {
            if (nums[i] + nums[j] == target) {
                return [i, j];
            }
        }
    }
}

console.log(twoSum([1, 2, 3, 4, 5, 6], 7))